01157619

Component

https://doi.org/10.3141/2142-05

http://scholar.google.com...amer&publication_year=2010

It is well recognized that the area of contact between cement paste and aggregates, known as the interfacial transition zone (ITZ), is one of the most vulnerable areas of concrete. The microstructure, chemistry, porosity, and mineralogy of this interface affect the adhesion between the aggregate and the cement paste and therefore, under certain conditions, dictate the performance of concrete. The traditional strategy for improving the ITZ has been the addition of pozzolanic materials having a close relation between surface area and particle size. However, the beneficial effects of these additions to the ITZ are diluted because the additives largely end up in the bulk of the cement paste. Research was done to show the benefit and practicality of depositing pozzolanic materials as thin films on the surface of aggregates to improve the ITZ. Preliminary results show that a small dose of these materials can significantly modify adhesion between aggregate and cement paste in the ITZ. The consequence is an overall improvement of the principal mechanical properties and a change in the microstructure of mortar. In particular, mortar made with a 0.0032 silica oxide–cement ratio deposited as a surface coating of just one-third of the total fine aggregates showed an average 35% improvement in compressive, flexural, and tensile strength at early ages along with decreased chloride penetrability. These results clearly indicate that the addition of silica oxides into concrete as thin films on aggregate surfaces has a high potential for improving the overall performance of concrete.

01157601

NANO10-0043

English

pp 29-33

2010

Transportation Research Record: Journal of the Transportation Research Board

9780309142779

Print

Figures (5) ; References (19) ; Tables (3)

Adhesion; Aggregates; Cement mortars; Cement paste; Compressive strength; Flexural strength; Mechanical properties; Microstructure; Nanotechnology; Pozzolan; Silicon dioxide; Tensile strength; Thin films

Interfacial transition zone

Materials; I32: Concrete

TRIS, TRB, ATRI

May 26 2010 3:05PM

• American Road Map for Research for Nanotechnology-Based Concrete Materials
• Carbon Nanofiber–Reinforced Cement-Based Materials
• Direct Synthesis of Carbon Nanofibers on Cement Particles
• Distribution of Carbon Nanofibers and Nanotubes in Cementitious Composites
• Enhancement of Reactive Powder Concrete via Nanocement Integration
• Exploratory Investigation of Nanomaterials to Improve Strength and Permeability of Concrete
• Laboratory Assessment of a Self-Healing Cementitious Composite
• Modeling Nanoindentation of Calcium Silicate Hydrate
• Molecular Dynamics Study of Interaction Between Corrosion Inhibitors, Nanoparticles, and Other Minerals in Hydrated Cement
• Molecular Dynamics to Understand the Mechanical Behavior of Cement Paste
• Nanocellulose and Microcellulose Fibers for Concrete
• Nanoengineering Ultra-High-Performance Concrete with Multiwalled Carbon Nanotubes
• Nanotechnology and Concrete: Concepts and Approach
• New Calcium Silicate Hydrate Network
• New Possibilities and Future Pathways of Nanoporous Thin Film Technology to Improve Concrete Performance
• Performance of Carbon Nanofiber–Cement Composites with a High-Range Water Reducer
• Scanning Transmission X-Ray Microscopic Study of Carbonated Calcium Silicate Hydrate
• Stability of Synthetic Calcium Silicate Hydrate Gels in Presence of Alkalis, Aluminum, and Soluble Silica
• Strength Enhancement of Cement Mortar with Carbon Nanotubes: Early Results and Potential